Keyboard and mouse will not work after post

Since your mouse and keyboard are working in the BIOS screens it tells you it is not a hardware issue. The issue is within Windows, between the bios settings and Windows, or with a driver, etc. You mentioned that you have also tried a USB keyboard/mouse and that did not work. (I assume you used a regular corded mouse and keyboard, not a wireless/bluetooth one).

Here are a few things you might try:

1) Go into the BIOS and load the default settings then try to restart the computer. Check to see if the mouse/keyboard are working.

2) If you can - pull the battery out of the machine, pull the power cord, and hold the power button down for a few seconds. Plug the charger in, leave the battery out, and try to start the computer. No luck, repeat but this time try with the battery in.

3) If the battery is not accessible (internal) many machines have a small pinhole “reset” switch on the bottom that disconnects the battery while the switch is pressed. Remove the charger, insert a paper clip end into the pinhole (usually has a battery symbol beside it) and push to hold the button inside down for 30 seconds or so. Reinstall the charger and start windows to see if the keyboard/touchpad have started working.

4) If the above steps have not resolved it, one other thing you might try is to open the machine up, find the BIOS battery (some are soldered in) and remove it for a few minutes. You can also try removing the battery and then shorting the + - pins on the battery holder with a wire (with the bios battery removed). Check the voltage on the battery if you have a volt meter. It should be 3V or better. Put the battery back in and try again.

5) If you can somehow force Windows 7 into safe mode (sometimes by shutting the machine off while it is booting into windows then restarting) you might also try to roll back to a previous restore point from before the problem started.

Hope this helps.